A look into the past of Iron County, Utah

The Pioneer Blast Furnace

Cedar City was settled by pioneers hoping to successfully mine and produce iron. This group of core settlers became known as the Iron Mission. After many early attempts with a small furnace, they got the process down and began construction on a much larger structure. Built in 1854 the second pioneer blast furnace produced the best quality iron seen in during the entire length of the Iron Mission. Even before beginning construction, the residents of Cedar City named this structure the Noble Furnace because of their expectations that this would be a “noble building.” The Noble Furnace proved much larger than its predecessor and also used a mechanical loading assembly.

Blueprints of the Noble Furnace taken from the Deseret Iron Company

Producing iron in the 19th century began with the combination of raw ore with a mixture of fuel and limestone. This was called a “charge” which filled or “burdened” the furnace. Many trials of each mixture were needed to get the right combination of ingredients. These were done in a smaller furnace or “cupola.” If a large charge was mixed incorrectly the lining of the furnace would fall off and need to be replaced – a process which could take months.

The replica furnace built to the exact dimensions of the pioneer furnace.

The fuel used by the pioneers was either wood-based charcoal or coal-based coke. Charcoal proved the fuel of choice at Iron City. It was created by burning or smoldering wood in an oxygen free environment. Coke is produced in a similar manner using coal and a coke oven. Using charcoal benefited the workers at Iron City because wood was readily available and it produced a softer more pliable piece of iron. Unfortunately, charcoal production uses a large number of trees.

Limestone served as a flux or catalyst that assisted in melting iron ore and binding to impurities. The furnace was lit and a constant temperature maintained through use of a water-powered bellows system. The ore mixture would heat up and separate – the heavier iron sank to the bottom while the impurities bound to the limestone rose to the top as “slag.” The pure iron was released when the furnace was “tapped,” then taken to the molding shop for further processing. Once cooled, the slag would be ground into cinder and discarded.